The work proposed here is a five-year continuation of an ongoing series of surveys of young men and women which began in 1975. The basic research design consists of two interconnected parts: (a) an annual survey of a nationally representative sample of about 18,000 seniors located in about 130 high schools, and (b) annual follow-up surveys mailed to a subset of each senior class (about 1,200 people) for the first six years following graduation. Thus the population of interest consists of most American men and women in the age range of about 18 through 24, monitored through a series of longitudinal surveys of sequential classes of high school seniors, an approach sometimes termed a chort-sequenial design. The measurement content of the study is quite broad, including the use of psychoactive drugs; attitudes, beliefs, and perceptions about drug use; and a wide range of other relevant psychosocial factors (behaviors, attitudes, and experiences) measured during high school and beyond. The study has two basic aims: (a) to monitor trends in drug use and related variables by providing accurate and detailed social indicator data annually: and (b) to uncover the causes, consequences, and maturational patterns associated with drug use, using the study's longitudinal data. The fact that the same study combines both of these aims and approaches enriches the data resources for both, and is highly cost-effective. Findings will be reported through several annual report series, as well as through journal articles, the mass media, and at least one major integrative book. The study is expected to facilitate the work of other researchers by providing archived data, survey instruments, related methodology, and basic referece volumes.